1. Technical Field
The present invention relates to a vehicle authentication device for performing authentication on whether or not a driver is a legitimate driver (possessor of vehicle etc.) between a vehicle and a carrying portable device when starting the drive of the vehicle.
2. Related Art
A vehicle authentication control device aiming to prevent theft of vehicle and illegal use is being used. The vehicle authentication control device exchanges unique identification information (hereinafter referred to as an ID) assigned to each vehicle through a wireless communication that uses a weak radio wave between an authentication device mounted on the vehicle and a portable device to determine whether a legitimate driver, and permits the startup of the engine and also unlocks a steering lock when determined as the legitimate driver (see e.g., Japanese Unexamined Patent Publication No. 2005-76263).
In the above vehicle authentication control device, the ID unique to the vehicle is stored in both the authentication device mounted on the vehicle and the portable device, and such an ID are matched to determine whether or not the legitimate driver, but the possibility the authentication device mounted on the vehicle might be illegally changed cannot be denied, and hence the security is vulnerable in this respect.
The measures for the above drawback, that is, illegal changing of the authentication device are believed to be taken by storing a storage area of the ID on the vehicle side not only in the authentication device, but also in parts such as an engine control unit for performing engine control and a steering lock unit for controlling the lock/unlock of the steering wheel based on the authentication result from the authentication device.
In other words, conventionally, the lock/unlock of the steering wheel has been performed with a mechanical key, but some kind of security measures became necessary for the steering lock unit with the appearance of recent electronic keys (key type not using mechanical key).
In the vehicle system of the electronic key type, since a unit (BCM) for performing the authentication with the portable device is arranged, redundantly loading the same wireless authentication function into the steering lock unit leads to increase in cost.
Therefore, the wireless authentication function is not loaded into the steering lock unit, and the authentication result performed by the BCM is transmitted to the steering lock unit via harness.
However, if the authentication result is flowed to the harness as simple data, a third person with bad intention may easily steal such data and imitate the data. There is thus a concern that the lock may be unlocked by providing the imitated data to the steering lock unit.
To eliminate such a concern, the BCM and the steering lock unit transmit the authentication result of the portable device using an encrypted signal, and the ID and the encryption are adopted to also verify the legitimacy of the BCM and the steering lock unit.